How can I remotly shutdown a windows machine

Reboot now:

shutdown /r /m \\computername /t 0

Shutdown now:

shutdown /s /m \\computername /t 0

In both examples, change the 0 to a number of seconds to delay if desired. Plenty of other options you can get from:

shutdown /?

You might also want to checkout Mark Russinovich's PsShutdown utility. It's similar to the native Windows shutdown command, but also allows you to logoff the console user or lock the console.

In Windows Remote Desktop hit ctrl+alt+END. Then click the Shut Down button.

Go to command prompt (start > run > cmd) on your workstation... and Type shutdown -r -m \xxx.xxx.xxx.xxx Replace xxx.xxx.xxx.xxx with the IP address or computer name of the remote machine. -r option is for restart, don't use -r if want to just shut down the system.

This can also be very fun